Schedule II - Condensed Financial Information of Registrant (Statements of Income (Parent Company)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Income Statements, Captions [Line Items]
Net investment gains	$ 202,397	$ 90,632	$ 103,000
Other income	3,396	4,177	2,596
Total revenues	11,166,499	9,455,466	8,098,925
Operating costs and expense	9,446,818	8,172,561	7,394,123
Income before income taxes	1,719,681	1,282,905	704,802
Federal income taxes:
Net federal income tax expense	(334,727)	(251,890)	(171,817)
Net income to common stockholders	1,381,062	1,022,490	530,670
Dividends from subsidiaries	22,807	520,251	617,424
Parent Company
Condensed Income Statements, Captions [Line Items]
Management fees and investment income including dividends from subsidiaries of $22,807, $520,251, and $617,424 for the years ended December 31, 2022, 2021 and 2020, respectively	32,585	548,512	654,485
Net investment gains	1,007	1,474	3,580
Other income	1,916	1,138	568
Total revenues	35,508	551,124	658,633
Operating costs and expense	192,175	214,995	166,892
Interest expense	129,633	144,837	145,417
Income before income taxes	(286,300)	191,292	346,324
Federal income taxes:
Federal income taxes provided by subsidiaries on a separate return basis	414,660	294,731	188,490
Federal income tax expense on a consolidated return basis	(258,776)	(226,900)	(139,679)
Net federal income tax expense	155,884	67,831	48,811
(Loss) income before undistributed equity in net income of subsidiaries	(130,416)	259,123	395,135
Equity in undistributed net income of subsidiaries	1,511,478	763,367	135,535
Net income to common stockholders	$ 1,381,062	$ 1,022,490	$ 530,670